The invention relates to an underbody panelling part of a wheel axle in the region of the wheel arch of a motor vehicle, and to a subassembly having an underbody panelling part of said type.
Against the background of the discussion regarding the reduction of CO2 emission of motor vehicles, measures for reducing fuel consumption play an ever greater role. These include, inter alia, the lowering of the air resistance of the vehicle. Whereas optimum solutions have long been sought in the case of vehicle body design, the reduction of the air resistance of the underbody of the vehicle has still not advanced very far. Here, however, there is major potential for improvement, because the underbody, after all, can account for approximately 20% of the overall air resistance.
In the region of the front axle with the steerable wheels, the particular challenge is to realize an underbody panelling which allows for the variable wheel position.
In this regard, DE 10 2010 018 779 A1 has proposed, generally, that a panelling part be held on the motor vehicle so as to be movable in a manner dependent on a pivoting movement of a link element. The manner of attachment is, however, not specified.
It is an object of the invention to provide an inexpensive underbody panelling part which can be easily arranged, in the region of a wheel axle, in the wheel arch, and which can realize an effective reduction in air resistance.
For this purpose, an underbody panelling part of a wheel axle in the region of the wheel arch of a motor vehicle is formed with a substantially plate-like main body. A first bearing point is provided which is formed on the main body and which can be rotatably connected to a transverse link of the motor vehicle, and a second bearing point is provided which is formed on the main body and which can be coupled to a wheel carrier or to a steering rod, such that the panelling part can be pivoted about the first bearing point with a pivoting movement of the wheel carrier. The rotatable connection to the transverse link serves to realize a pivot point which is situated very close to the center of rotation of the wheel carrier, such that the pivoting of the underbody panelling part follows the pivoting of the wheel carrier as closely as possible. In this way, the formation of excessively large gaps is prevented. The pivoting movement required for following the steering movement is transmitted to the panelling part via the second bearing point by a component which performs the steering movement, specifically the wheel carrier or the steering rod.
The underbody panelling part is preferably composed of a lightweight, rigid material which is weather-resistant and which is not sensitive to shocks, for example a fiber-reinforced plastics material.
The invention also relates to a subassembly having an underbody panelling part according to the invention. The subassembly furthermore includes a pendulum rod by which the second bearing point is connected to the wheel carrier or to the steering rod.
The pendulum rod may be mounted at both sides by way of ball joints.
As an alternative to this, the subassembly according to the invention provides that a rigid connection is provided, by way of which the second bearing point is connected to the wheel carrier or to the steering rod.
It is also contemplated for a variable-length connection to be provided between the underbody panelling part and the wheel carrier in order, in the event of collisions with adjacent components, for example in extreme positions of the steering system or in the event of constriction of the wheel arch as a result of severe fouling, ice or snow deposits, to realize a compensatory clearance for the underbody panelling part. The connection between the underbody panelling part and the wheel carrier could, for example, be designed to be elastically flexible under pressure and/or under tension.
At the first bearing point, there is preferably provided a rotary joint which, in the installed state, connects the underbody panelling part to the transverse link. It has been found to be sufficient for only a rotational degree of freedom to be provided at this location.
The rotary joint is preferably a sealed rotary plain bearing, composed for example of a suitable plastic.
The positioning of the articulation points on the underbody panelling part and on the wheel carrier and/or the steering rod is performed with the aim of minimizing a relative movement of the underbody panelling part relative to the articulated and spring-mounted wheel. By means of the pendulum rod, the angular movements can be distributed in balanced fashion across all kinematic states, such that no excessive relative angles arise in relation to the initial state during straight-ahead travel and relative to the adjacent components.
A gap that necessarily arises between the underbody panelling part and adjacent components can be covered through the fitting of a flexible material, for example a brush seal.
The underbody panelling part may also have the effect of at least partially sealing off the wheel arch region against the ingress or emergence of air flows.
The underbody panelling part preferably has an upwardly curved edge situated at the front in the vehicle longitudinal direction. The curved geometry reliably prevents the possibility of an air flow exerting a force on the underbody panelling part from above.
If, in the case of wheel arches through which cooling air flows, it is necessary to ensure good ventilation of the wheel arch, the underbody panelling part may, optionally, at its end directed toward the vehicle rear end, delimit an air duct which is oriented substantially horizontally. The air duct permits an outflow of air from the wheel arch in a substantially horizontally directed air stream without turbulence, which turbulence would otherwise increase the air resistance.
The optional air duct may be formed by a gap between the underbody panelling part and an adjacent vehicle body section, through which gap the air can flow in parallel along the underbody of the vehicle.
Through the provision of an underbody panelling part of this type, it is possible for the ram lip provided in the region of the front of the vehicle, or a ram body arranged there, to be decreased in size or omitted entirely.
The overall geometry of the underbody panelling part may be adapted by a person skilled in the art to the geometry of the wheel arch region and the required free travel of the underbody panelling part in all potential operating states and driving states.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.